Preparation of aromatic fluoro compounds

ABSTRACT

The present invention relates to a process for the preparation of 4,4&#39;-difluorobenzophenone. 4,4-difluorobenzophenone may be prepared by diazotization of 4,4&#39;-diamino-diphenylmethane in anhydrous or concentrated aqueous hydrogen fluoride, decomposition of the diazonium fluoride thus produced to yield 4,4&#39;-difluoro-diphenylmethane and oxidation of 4,4&#39;-difluoro-diphenylmethane to yield 4,4&#39;-difluorobenzophonone. 
     Thus, according to the present invention, there is provided a process for the preparation of 4,4&#39;-difluorobenzophenone which comprises the following steps: 
     (1) diazotization of 4,4&#39;-diamino-diphenylmethane in anhydrous or concentrated aqueous hydrogen fluoride to yield a solution of a corresponding diazonium fluoride; and 
     (2) (i) thermally decomposing the diazonium fluoride in the solution thus produced to yield 4,4&#39;-difluoro-diphenylmethane and (ii) subsequently oxidizing the 4,4&#39;-difluoro-diphenylmethane to yield 4,4&#39;-difluorobenzophenone.



